高寒草甸植物叶片氮和磷重吸收率对养分添加的响应及机理

黎鹏宇; 李佳璞; 何奕成; 田大栓; 纪宝明

doi:10.12171/j.1000-1522.20230093

高寒草甸植物叶片氮和磷重吸收率对养分添加的响应及机理

doi: 10.12171/j.1000-1522.20230093

黎鹏宇^{1, 2,},
李佳璞³,
何奕成^{2, 4},
田大栓²,
纪宝明^1, ,

1.
北京林业大学草业与草原学院，北京 100083
2.
中国科学院地理科学与资源研究所，北京 100101
3.
南京农业大学资源与环境科学学院，江苏南京 210095
4.
中国农业大学草业科学与技术学院，北京 100193

基金项目: 国家重点研发计划（2017YFA0604802、2017YFA0604801）。

详细信息

作者简介:
黎鹏宇。主要研究方向：草地生态学。Email：lpy126bk@126.com　地址：100083 北京市海淀区清华东路35号

责任作者:
纪宝明，教授，博士生导师。主要研究方向：土壤微生物生态学。Email：baomingji@bjfu.edu.cn　地址：同上。

中图分类号: Q945.79
计量
- 文章访问数: 64
- HTML全文浏览量: 18
- PDF下载量: 9
- 被引次数: 0
出版历程
- 录用日期: 2023-08-24
- 网络出版日期: 2023-08-25

Responses and mechanisms of leaf nitrogen and phosphorus resorption efficiency to nutrient addition in an alpine meadow

Li Pengyu^{1, 2
,},
Li Jiapu³,
He Yicheng^{2, 4},
Tian Dashuan²,
Ji Baoming^{1
, ,}

1.
School of Grassland Science, Beijing Forestry University, Beijing 100083, China
2.
Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
3.
College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
4.
College of Grassland Science and Technology, China Agricultural University, Beijing 100193, China

摘要

摘要: 目的叶片养分重吸收是植物从凋落叶片中回收养分并转运到植物其他组织和器官的能力，是植物养分利用的主要策略之一。前人研究表明氮或磷添加对植物叶片养分重吸收效率的影响表现为负效应或无作用两种情况，但目前关于氮和磷添加及交互作用对植物叶片养分重吸收效率的影响及机理的研究还比较少。方法本研究以高寒草甸优势植物为研究对象，基于氮和磷添加两因子正交实验，旨在揭示高寒植物叶片养分重吸收效率对养分添加的响应及机制。结果研究发现（1）禾本科和杂类草叶片氮重吸收效率对氮添加的响应表现为增加或不响应，但4种植物叶片磷重吸收效率不受氮添加的影响。（2）磷添加不影响所有植物叶片氮重吸收效率和两种杂类草叶片磷重吸收效率，但提升了禾本科叶片的磷重吸收效率。（3）氮和磷共同添加降低了垂穗披碱草、灰苞蒿和鹅绒委陵菜的叶片氮重吸收效率，但提升了发草叶片的氮重吸收效率。此外，氮和磷同时添加不影响4种植物的叶片磷重吸收效率。结论综上所述，本研究指示出养分富集背景下高寒植物采取了3种养分重吸收策略，即对外源获取的养分全部重吸收（绿叶养分增加但凋落叶不增加）、部分重吸收（绿叶和凋落叶同时增加，但凋落叶增加较慢）和不进行重吸收（绿叶和凋落叶均增加，但凋落叶的幅度大于或等于绿叶；或绿叶和凋落叶不响应）。这些研究结果揭示了高寒植物养分内循环策略的多样性和互补性。
- 高寒草甸 /
- 养分添加 /
- 氮重吸收效率 /
- 磷重吸收效率
Abstract: Objective Leaf nutrient resorption is the ability of plants to recycle nutrients from senescent leaves and transport them to other tissues and organs, which is one of the main strategies for plant nutrient utilization. Previous studies show that nitrogen (N) or phosphorus (P) addition generally reduces or does not affect leaf nutrient resorption efficiency. However, there are still few studies on the effects of N and P addition and their interaction on leaf nutrient resorption efficiency and the underlying mechanisms. Method To answer this question, we performed an experiment of N and P addition in an alpine meadow, measuring leaf nutrient resorption efficiency in four dominant species (Elymus nutans, Deschampsia cespitosa, Artemisia roxburghiana, Potentilla anserina). Result We found that (i) N addition had positive effects or no impact on leaf N resorption efficiency (NRE) in graminoids and forbs, while it did not affect P resorption efficiency (PRE) among four plant species. (ii) P addition had no effect on leaf NRE among four species or PRE in forbs, but it significantly increased leaf PRE in graminoids. (iii) N + P addition together reduced leaf NRE in E. nutans, A. roxburghiana and P. anserina, but increased NRE in D. cespitosa. Moreover, the combination of N + P addition did not affect leaf PRE among four species. Conclusion Overall, our study indicates that alpine plants adopt three nutrient resorption strategies for more nutrient supply: full resorption (increased green leaf nutrient but no change in senescent leaf), partial resorption (more increase in green leaf nutrient than senescent leaf) and no resorption (similar increase in green and senescent leaf nutrient). These findings reveal the diversity and complementarity of plant strategies of nutrient internal cycle in alpine grasslands.
- alpine meadow /
- nutrient addition /
- nitrogen resorption efficiency /
- phosphorus resorption efficiency

HTML全文

图 1 沿土壤养分梯度植物养分重吸收效率以及对应的绿叶和凋落叶养分的不同响应概念图

Figure 1. Conceptual figure of divergent responses of plant nutrient resorption efficiency, and green and senescent leaf nutrients along with soil nutrient gradient

下载: 全尺寸图片幻灯片

图 2 4种植物叶片氮重吸收效率对氮添加（N）、磷添加（P）和氮磷同时添加（NP）的响应

^、*分别表示在 P < 0.1、0.05水平上处理与对照差异显著。下同。^, * indicate a significant treatment effect compared with control treatment at P < 0.1, 0.05 respectively. The same below.

Figure 2. Responses of nitrogen resorption efficiency in four dominant species to nitrogen (N), phosphorus (P) addition and their combined treatments (NP)

下载: 全尺寸图片幻灯片

图 3 氮添加（N）、磷添加（P）和氮磷同时添加（NP）对4种植物绿叶和凋落叶氮含量的影响

不同小写字母表示差异显著（P < 0.05）。下同。Different lowercase letters indicate a significant difference between control and treatment (P < 0.05). The same below.

Figure 3. Effects of nitrogen addition (N), phosphorus addition (P) and their combined treatments (NP) on nitrogen concentration in green and senescent leaves of four dominant plants

下载: 全尺寸图片幻灯片

图 4 4种植物养磷重吸收效率对氮添加（N）、磷添加（P）和氮磷同时添加（NP）的响应

***表示在 P < 0.001水平上处理与对照差异显著。*** indicates a significant treatment effect compared with control treatment at P < 0.001.

Figure 4. Responses of phosphorus resorption efficiency in four dominant species to nitrogen (N), phosphorus (P) addition and their combined treatments (NP)

下载: 全尺寸图片幻灯片

图 5 氮添加（N）、磷添加（P）和氮磷同时添加（NP）对4种植物绿叶和凋落叶磷含量的影响

Figure 5. Effects of nitrogen addition (N), phosphorus addition (P) and their combined treatments (NP) on phosphorus concentration in green and senescent leaves of four dominant plants

下载: 全尺寸图片幻灯片

图 6 土壤有效氮或有效磷与四种植物绿叶和凋落叶的养分含量之间的关系

Figure 6. Relationship between soil available nitrogen or phosphorus and green or senescent leaf nutrient content in four species

下载: 全尺寸图片幻灯片

表 1 氮、磷添加及其交互作用对4种植物绿叶和凋落叶的养分含量以及氮和磷重吸收效率影响的两因素方差分析

Table 1. Two-way ANOVA on the effects of nitrogen and phosphorous addition on green and senescent leaf nutrient concentration, and nutrient resorption efficiency

物种 Species	指标 Index	氮添加 N addition	磷添加 P addition	氮磷交互作用 N × P addition
垂穗披碱草 Elymus nutans	绿叶氮含量 Green leaf nitrogen content	9.503**	0.481	0.886
	凋落叶氮含量 Senescent leaf nitrogen content	0.823	6.819*	0.488
	氮重吸收效率 NRE	0.766	39.198***	15.953**
	绿叶磷含量 Green leaf phosphorus content	6.794*	131.218***	0.053
	凋落叶磷含量 Senescent leaf phosphorus content	1.327	30.389***	14.597**
	磷重吸收效率 PRE	12.46**	12.29**	22.77***
发草 Deschampsia cespitosa	绿叶氮含量 Green leaf nitrogen content	25.652***	0.227	3.9
	凋落叶氮含量 Senescent leaf nitrogen content	0.117	0.472	3.071
	氮重吸收效率 NRE	24.287***	0.161	19.047***
	绿叶磷含量 Green leaf phosphorus content	21.625***	28.256***	1.834
	凋落叶磷含量 Senescent leaf phosphorus content	2.227	18.638**	0.988
	磷重吸收效率 PRE	5.35*	0.009	6.918*
灰苞蒿 Artemisia roxburghiana	绿叶氮含量 Green leaf nitrogen content	1.217	3.466	2.466
	凋落叶氮含量 Senescent leaf nitrogen content	29.555***	6.503*	2.6
	氮重吸收效率 NRE	0.701	2.203	0.58
	绿叶磷含量 Green leaf phosphorus content	10.669**	56.367***	2.207
	凋落叶磷含量 Senescent leaf phosphorus content	9.194*	54.704***	2.674
	磷重吸收效率 PRE	0.313	1.532	0.005
鹅绒委陵菜 Potentilla anserina	绿叶氮含量 Green leaf nitrogen content	7.005*	1.971	0.017
	凋落叶氮含量 Senescent leaf nitrogen content	72.432***	1.885	8.259*
	氮重吸收效率 NRE	8.84*	5.448*	4.439
	绿叶磷含量 Green leaf phosphorus content	0.734	67.76***	0.95
	凋落叶磷含量 Senescent leaf phosphorus content	0.353	33.474***	1.9
	磷重吸收效率 PRE	4.163	1.476	0.762

下载: 导出CSV

参考文献(52)

[1]	Aerts R, Chapin F S. The mineral nutrition of wild plants revisited: a re-evaluation of processes and patterns[M]//Fitter A H, Raffaelli D G. Advances in Ecological Research. New York: Academic Press, 1999.
[2]	Jackson R B, Schenk H J, Jobbágy E G, et al. Belowground consequences of vegetation change and their treatment in models[J]. Ecological Applications, 2000, 10(2): 470−483. doi: 10.1890/1051-0761(2000)010[0470:BCOVCA]2.0.CO;2
[3]	Zhao Q, Guo J, Shu M, et al. Impacts of drought and nitrogen enrichment on leaf nutrient resorption and root nutrient allocation in four Tibetan plant species[J]. Science of the Total Environment, 2020, 723: 138106. doi: 10.1016/j.scitotenv.2020.138106
[4]	Wang F, Fang X, Wang G G, et al. Effects of nutrient addition on foliar phosphorus fractions and their resorption in different-aged leaves of Chinese fir in subtropical China[J]. Plant and Soil, 2019, 443(1−2): 41−54. doi: 10.1007/s11104-019-04221-8
[5]	Kou L, Wang H, Gao W, et al. Nitrogen addition regulates tradeoff between root capture and foliar resorption of nitrogen and phosphorus in a subtropical pine plantation[J]. Trees, 2017, 31: 77−91. doi: 10.1007/s00468-016-1457-7
[6]	Li X, Liu J, Fan J, et al. Combined effects of nitrogen addition and litter manipulation on nutrient resorption of Leymus chinensis in a semi-arid grassland of northern China. [J]. Plant Biology (Stuttgart, Germany), 2014, 17(1): 9−15.
[7]	Wang M, Murphy M T, Moore T R. Nutrient resorption of two evergreen shrubs in response to long-term fertilization in a bog[J]. Oecologia, 2014, 174(2): 365−377. doi: 10.1007/s00442-013-2784-7
[8]	Zhang Y, Yang G, Shi F, et al. Biomass allocation between leaf and stem regulates community-level plant nutrient resorption efficiency response to nitrogen and phosphorus additions in a temperate wetland of Northeast China[J]. Journal of Plant Ecology, 2021, 14(1): 58−66. doi: 10.1093/jpe/rtaa077
[9]	Lu J, Yang M, Liu M, et al. Nitrogen and phosphorus fertilizations alter nitrogen, phosphorus and potassium resorption of alfalfa in the Loess Plateau of China[J]. Journal of Plant Nutrition, 2019, 42: 1−13. doi: 10.1080/01904167.2018.1509996
[10]	Van Heerwaarden L M, Toet S, Aerts R. Nitrogen and phosphorus resorption efficiency and proficiency in six sub-arctic bog species after 4 years of nitrogen fertilization[J]. Journal of Ecology, 2003, 91(6): 1060−1070. doi: 10.1046/j.1365-2745.2003.00828.x
[11]	Su Y, Ma X, Gong Y, et al. Responses and drivers of leaf nutrients and resorption to nitrogen enrichment across northern China’s grasslands: a meta-analysis[J/OL]. Catena, 2021, 199(1): 105110[2022−10−09]. https://doi.org/10.1016/j.catena.2020.105110.
[12]	You C, Wu F, Yang W, et al. Does foliar nutrient resorption regulate the coupled relationship between nitrogen and phosphorus in plant leaves in response to nitrogen deposition?[J]. Science of the Total Environment, 2018, 645: 733−742. doi: 10.1016/j.scitotenv.2018.07.186
[13]	See C R, Yanai R D, Fisk M C, et al. Soil nitrogen affects phosphorus recycling: foliar resorption and plant–soil feedbacks in a northern hardwood forest[J]. Ecology, 2015, 96(9): 2488−2498. doi: 10.1890/15-0188.1
[14]	Liu Y, Li L, Li X, et al. Effect of nitrogen and phosphorus addition on leaf nutrient concentrations and nutrient resorption efficiency of two dominant alpine grass species[J]. Journal of Arid Land, 2021, 13(10): 1041−1053. doi: 10.1007/s40333-021-0080-7
[15]	Mao R, Zeng D-H, Zhang X-H, et al. Responses of plant nutrient resorption to phosphorus addition in freshwater marsh of Northeast China[J/OL]. Scientific Reports, 2015, 5: 8097 [2022−10−07]. https://www.nature.com/articles/srep08097.
[16]	Li L J, Zeng D H, Mao R, et al. Nitrogen and phosphorus resorption of Artemisia scoparia, Chenopodium acuminatum, Cannabis sativa, and Phragmites communis under nitrogen and phosphorus additions in a semiarid grassland, China[J]. Plant, Soil and Environment, 2012, 58(10): 446−451. doi: 10.17221/6339-PSE
[17]	Lü X T, Reed S C, Yu Q, et al. Nutrient resorption helps drive intra-specific coupling of foliar nitrogen and phosphorus under nutrient-enriched conditions[J]. Plant and Soil, 2016, 398(1): 111−120.
[18]	Yuan Z Y, Chen H Y H. Global-scale patterns of nutrient resorption associated with latitude, temperature and precipitation[J]. Global Ecology and Biogeography, 2009, 18(1): 11−18. doi: 10.1111/j.1466-8238.2008.00425.x
[19]	Zhang J, Li H, Shen H, et al. Effects of nitrogen addition on nitrogen resorption in temperate shrublands in northern China[J/OL]. PloS One, 2015, 10(6): e0130434 [2022-12-13]. http://doi.org/10.1371/journal.pone.0130434.
[20]	He M, Yan Z, Cui X, et al. Scaling the leaf nutrient resorption efficiency: Nitrogen vs phosphorus in global plants[J]. The Science of the Total Environment, 2020, 729: 138920. doi: 10.1016/j.scitotenv.2020.138920
[21]	Tateno R, Takeda H. Nitrogen resorption efficiency of 13 tree species of a cool temperate deciduous forest in Central Japan[J]. Journal of Forest Research, 2018, 23(2): 91−97. doi: 10.1080/13416979.2018.1432303
[22]	Chen H, Xu B, Wei S, et al. Nutrient resorption and phenolics concentration associated with leaf senescence of the subtropical mangrove aegiceras corniculatum: implications for nutrient conservation[J]. Forests, 2016, 7(11): 290.
[23]	Urbina I, Grau O, Sardans J, et al. High foliar K and P resorption efficiencies in old-growth tropical forests growing on nutrient-poor soils[J]. Ecology and Evolution, 2021, 11(13): 8969−8982. doi: 10.1002/ece3.7734
[24]	Wright I J, Westoby M. Nutrient concentration, resorption and lifespan: leaf traits of Australian sclerophyll species[J]. Functional Ecology, 2003, 17(1): 10−19. doi: 10.1046/j.1365-2435.2003.00694.x
[25]	Franklin O, Ågren G I. Leaf senescence and resorption as mechanisms of maximizing photosynthetic production during canopy development at N limitation[J]. Functional Ecology, 2002, 16(6): 727−733. doi: 10.1046/j.1365-2435.2002.00674.x
[26]	Chen J, Groenigen K. J. V, Hungate B. A, et al. Long-term nitrogen loading alleviates phosphorus limitation in terrestrial ecosystems[J]. Global Change Biology, 2020, 26(9): 5077−5086. doi: 10.1111/gcb.15218
[27]	Lü X, Reed S, Yu Q, et al. Convergent responses of nitrogen and phosphorus resorption to nitrogen inputs in a semiarid grassland[J]. Global Change Biology, 2013, 19(9): 2775−2784. doi: 10.1111/gcb.12235
[28]	Yuan Z Y, Chen H Y H. Negative effects of fertilization on plant nutrient resorption[J]. Ecology, 2015, 96(2): 373−380. doi: 10.1890/14-0140.1
[29]	Gerdol R, Iacumin P, Brancaleoni L. Differential effects of soil chemistry on the foliar resorption of nitrogen and phosphorus across altitudinal gradients[J]. Functional Ecology, 2019, 33(7): 1351−1361. doi: 10.1111/1365-2435.13327
[30]	Vourlitis G L, Lobo F de A, Lawrence S, et al. Nutrient resorption in tropical savanna forests and woodlands of central Brazil[J]. Plant Ecology, 2014, 215(9): 963−975. doi: 10.1007/s11258-014-0348-5
[31]	Yan Z B, Kim N, Han X W, et al. Effects of nitrogen and phosphorus supply on growth rate, leaf stoichiometry, and nutrient resorption of Arabidopsis thaliana[J]. Plant and Soil, 2014, 388: 147−155.
[32]	Chen F S, Niklas K J, Liu Y, et al. Nitrogen and phosphorus additions alter nutrient dynamics but not resorption efficiencies of Chinese fir leaves and twigs differing in age[J]. Tree Physiology, 2015, 35(10): 1106−1117. doi: 10.1093/treephys/tpv076
[33]	Hidaka A, Kitayama K. Allocation of foliar phosphorus fractions and leaf traits of tropical tree species in response to decreased soil phosphorus availability on Mount Kinabalu, Borneo[J]. Journal of Ecology, 2011, 99(3): 849−857. doi: 10.1111/j.1365-2745.2011.01805.x
[34]	Vitousek P. Nutrient cycling and nutrient use efficiency[J]. American Naturalist, 1982, 119(4): 553−572. doi: 10.1086/283931
[35]	Zhang M, Zhang L, Yao X, et al. Co-Evaluation of Plant Leaf Nutrient Concentrations and Resorption in Response to Fertilization under Different Nutrient-Limited Conditions[J]. Diversity-Basel, 2022, 14(5): 385.
[36]	Drenovsky R, Richards J. Low leaf N and P resorption contributes to nutrient limitation in two desert shrubs[J]. Plant Ecology, 2006, 183: 305−314. doi: 10.1007/s11258-005-9041-z
[37]	符义稳, 田大栓, 牛书丽, 等. 氮磷添加和干旱对高寒草甸优势植物叶片化学计量的影响[J]. 北京林业大学学报, 2020, 42(05): 115−123. doi: 10.12171/j.1000-1522.20190469 Fu Y W, Tian D S, Niu S L, et al. Effects of nitrogen, phosphorus addition and drought on leaf stoichiometry in dominant species of alpine meadow[J]. Journal of Beijing Forestry University, 2020, 42(5): 115−123. doi: 10.12171/j.1000-1522.20190469
[38]	Li N, Wang G, Yang Y, et al. Plant production, and carbon and nitrogen source pools, are strongly intensified by experimental warming in alpine ecosystems in the Qinghai-Tibet Platea[J]. Soil biology & biochemistry, 2011, 43(5): 942−953.
[39]	Yang Z, Gao J, Zhao L, et al. Linking thaw depth with soil moisture and plant community composition: effects of permafrost degradation on alpine ecosystems on the Qinghai-Tibet Plateau[J]. Plant and Soil, 2013, 367(1-2): 687−700. doi: 10.1007/s11104-012-1511-1
[40]	Zhao X, Zhou X. Ecological basis of alpine meadow ecosystem management in Tibet: Haibei alpine meadow ecosystem research station[J]. Ambio, 1999, 28: 642−647.
[41]	杨晓霞, 任飞, 周华坤, 等. 青藏高原高寒草甸植物群落生物量对氮、磷添加的响应[J]. 植物生态学报, 2014, 38(2): 159−166. doi: 10.3724/SP.J.1258.2014.00014 Yang X X, Ren F, Zhou H K, et al. Responses of plant community biomass to nitrogen and phosphorus additions in an alpine meadow on the Qinghai-Xizang Plateau[J]. Chinese Journal of Plant Ecology, 2014, 38(2): 159−166. doi: 10.3724/SP.J.1258.2014.00014
[42]	Butler O M, Elser J J, Lewis T, et al. The phosphorus-rich signature of fire in the soil-plant system: a global meta-analysis[J]. Ecology Letters, 2018, 21(3): 335−344. doi: 10.1111/ele.12896
[43]	Borer, E T, Seabloom, E W, Gruner, D S, et al. Herbivores and nutrients control grassland plant diversity via light limitation[J]. Nature, 2014, 508(517): 520.
[44]	Borer E T, Harpole W S, Adler P B, et al. Finding generality in ecology: a model for globally distributed experiments[J]. Methods in Ecology and Evolution, 2014, 5(1): 65−73. doi: 10.1111/2041-210X.12125
[45]	Boerner R E J. Foliar Nutrient Dynamics and Nutrient Use Efficiency of Four Deciduous Tree Species in Relation to Site Fertility[J]. Journal of Applied Ecology, 1984, 21(3): 1029−1040. doi: 10.2307/2405065
[46]	Zong N, Song M, Zhao G, et al. Nitrogen economy of alpine plants on the north Tibetan Plateau: Nitrogen conservation by resorption rather than open sources through biological symbiotic fixation[J]. Ecology and Evolution, 2020, 10(4): 2051−2061. doi: 10.1002/ece3.6038
[47]	Liang D, Zhang J, Zhang S. Patterns of nitrogen resorption in functional groups in a Tibetan alpine meadow[J]. Folia Geobotanica, 2015, 50(3): 267−274. doi: 10.1007/s12224-015-9217-9
[48]	安卓, 牛得草, 文海燕, 等. 氮素添加对黄土高原典型草原长芒草氮磷重吸收率及C∶N∶P化学计量特征的影响[J]. 植物生态学报, 2011, 35(8): 801−807. doi: 10.3724/SP.J.1258.2011.00801 An Z, Niu D C, Wen H Y, et al. Effects of N addition on nutrient resorption efficiency and C∶N∶P stoichiometric characteristics in Stipa bungeana of steppe grasslands in the Loess Plateau, China[J]. Chinese Journal of Plant Ecology, 2011, 35(8): 801−807 doi: 10.3724/SP.J.1258.2011.00801
[49]	Dong W Y, Zhang X Y, Liu X Y, et al. Responses of soil microbial communities and enzyme activities to nitrogen and phosphorus additions in Chinese fir plantations of subtropical China[J]. Biogeosciences, 2015, 12(18): 5537−5546. doi: 10.5194/bg-12-5537-2015
[50]	Zemunik G, Turner B L, Lambers H, et al. Diversity of plant nutrient-acquisition strategies increases during long-term ecosystem development[J/OL]. Nature Plants, 2015, 1(5): 15050 [2022−10−15]. https://www.nature.com/articles/nplants201550.
[51]	Delgado Baquerizo M, Maestre F T, Gallardo A, et al. Decoupling of soil nutrient cycles as a function of aridity in global drylands[J]. Nature, 2013, 502: 672−676. doi: 10.1038/nature12670
[52]	Du E, Terrer C, Pellegrini A F A, et al. Global patterns of terrestrial nitrogen and phosphorus limitation[J]. Nature Geoscience, 2020, 13(3): 221−226. doi: 10.1038/s41561-019-0530-4